The 640K memory barrier for the IBM PC has been broken. Advanced Peripheral Products, which specialises in importing tried and tested PC peripherals from the US, is now marketing the Tall Trees Systems JRAM card.
It offers memory expansion in 512K increments up to 2.5MB, and operates with the aid of a hardware pager in the form of a software-controlled high-speed memory chip. This allows each 64KB of memory to be referenced through any 64K address boundary accessed by the CPU.
APP is at the moment offering the cards at an end-user price of £795, but is currently negotiating to have cards shipped without chips. This means it might be possible to use cheaper chips obtained in this country.